Hand surveying instrument



Jan. 24, 1956 L. CHURGIN ETAL 2,731,873

HAND SURVEYING INSTRUMENT Filed Jan. 24, 1952 2 Sheets-Sheet l Jan. 24, 1956 L, CHURGIN ETAL HAND SURVEYING INSTRUMENT 2 Sheets-Sheet 2 Filed Jan. 24, 1952 INVENTOR.

6 7 6 8 fi j w 2,731,873 HAND SURVEYING INSTRUMENT Leopold Churgin, New York, N. Y., md Donald N. Grundberg, Stoneham, Mass, assignors to C. L. Berger &l:l Sons, Inc., Boston, Mass, a corporation of Massac usetts Application January 24, 1952, Serial No.

2 Claims. (Cl. 88-2.3)

This invention relates generally to surveying instruents, and more particularly to an improved form of The invention lies in specific structural improvements which permit not only greater simplicity in the manufacturing process, but also facilitate the use of the device.

It is among the principal objects of the present invention to provide Locke level structure in which Still another object of the invention lies in the provision of a Locke level having an improved leveling element incorporating an adjustable mirror.

A further object of the invention lies in the provision of improved leveling element structure having mirror adjustment means which may be operated without disassembling the entire instrument.

A feature of the invention lies in the provision of Locke level structure which is substantially dustproof after as sembly.

Another feature of the invention lies in the provision of Locke level structure having the above described in which the cost of fabrication may be of a relatively low order, with consequent wide sale, distribution and use.

Another object of the invention lies in the provision of Locke level structure possessing the above-mentioned advantages which may be of exceptionally sturdy structure, thus permitting a relatively long, trouble-free, use ful life.

These objects and features, as well as other incidental ends and advantages, will become more clearly apparent during the course of the following disclosure, and be pointed out in the appended claims.

On the drawing, to which reference will be made in the specification, similar reference characters have been em ployed to designate corresponding parts throughout the several views.

Figure l is a view the invention.

Figure 2 is a longitudinal central sectional view as seen from the plane 22 on Figure 1.

Figure 3 is a view in perspective showing the focusing tube element which comprises a part of the embodiment.

Figure is a fragmentary enlarged vertical sectional view as seen from the plane 44 on Figure 2.

Figure 5 is an elevational view of the focusing tube element shown on Figure 3.

in perspective of an embodiment of d rates Patcnt 0 Figure 6 is an enlarged fragmentary view in perspective showing the leveling element which comprises another part of the embodiment.

Figure sectional Figure substantially less tube element 10, so as to permit a sliding fit.

mounting 36 provides means for supporting a which is of a convex type,

The lens lens 38 30 and are disposed approximately apart from each other upon the curved surface. The amount of clearance between the main tube element 10 and the tube 30 is shown to an exaggerated degree on the drawing for purposes of clarity. Disposed approximately 120 from the axes of the pads 40-46 is an oval shaped groove 48 in which there is disposed a resilient leaf spring 5t). The spring 50 includes a forwardly disposed terminal 52, and

inner surface of the element 10 at five points, namely the four alignment pads 40-46 and the portion 56 of the cylinder 30 with surface of the cylinder 30 to close tolerances with respect to the inner surface of the element 10. it is thus pos sible to materially reduce the machining involved in the fitting of these two parts.

The cylinder 30 is moved with respect to the element 10 by means of a focussing knob in the form of an adjusting nut 58 which extends through a slot 59 (see Fig. 1) in the element 10. This movement is facilitated by a curved guide plate 60 which rides along the outer surface 24 of the same.

The leveling element includes a fixed supporting member 62 upon which the mirror positioning member 64 is slidably mounted.

The fixed member 62 is preferably in the form of a e. sa saud sc n r lly. irr ul configuration. .It.

includes a rearwardly disposed surface 66, a forwardly disposed surface 68, an outer cylindrical surface 70, the radius of which substantially equals thatwof the inner surface 26, and a large irregularly shaped channel 72. The lower surface 74 of the channel 72 is planar, to provide a support for the sliding of the mirror supporting member 64 thereover. The member 64 is urged to contact the surface 74 by a small leaf spring 76 which is maintained in a groove 78., A bubble tube 80 which may be of conventional design is maintained in a recess 82 (see Figure 8), the same being positively maintained in posia tion when the member 62 is fastened to the tube element by means of screws 81 and 83.

The mirror positioning member 64 is generally trapezoidal in configuration and includes a lower surface 84, a forwardly disposed vertical surface 86, an angularly disposed supporting surface 88 upon which there is mounted a mirror 90 having the usual index lines-92. A countersunk adjusting slot 94 cooperating with a set screw 96 provides means for locking the position of the mirror supporting member 64 with respect to the fixed member 62.

The set screw 96 includes a head portion'98 having a screw driver engagement slot 100, aswell as a threaded shaft portion 102 having a second screw driver engaging slot 104. The same is threadedly engaged in the hole 103 within the opening 105 in the elment 10. A recess 106 accommodates the head of an adjusting screw 108, the same permitting fine member 64 with respect to the bubble tube 80.

During the assembly of the device, the mirror positioning member 64 may be mounted within the fixed member 62 by means of the set screw 96, the slot 100 being employed to tighten the same. When the entire leveling element 14 is installed within the tube element 10, the slot 100 can no longer be conveniently reached. Subsequent adjustment is made by loosening the screw 96, using the slot 104. Any adjustments made after assembly may be accomplished by removing the cover element 18 to permit access to the screw 108, the screw 96 being first loosened from outside the element 10 to permit relative movement between the memberes 62 and 64.

The eye piece element 16 includes a cap member 116 (see Figure 9). The same is threadedly engageable upon the rearward end of the tube element 10 and includes an annular knurled surface 118 as well as a stepped machined surface 120. As is the case with most optical instruments, it is desirable that the eye piece have other than a truly planar surface to avoid undesirable reflections. Thus the surface 120 is made up of a plurality of stepped circular surfaces 121, each step being approximately five one thousandths (.005) inch from the succeeding step. This arrangement permits all of the surfaces 121 to be macbined simultaneously, using a tool (not shown) having a stepped cutting edge. A transparent dust sealing member of glass or synthetic resin 124 prevents entry of contaminating material through the viewing opening 122.

The cover element 18 is of similar structure including a threaded collar 126 which serves to maintain in position a transparent protective cover 128, preferably formed from planar glass or other similar material.

If desired, the screw 83 may be formed as shown on Figures 1 and 3 to include a large head having a transverse orifice 113 therein. A lanyard 114 is engaged in this orifice to provide means for carrying the entire device 9 about the neck of the user, thus avoiding possibility of damage while carrying.

adjustment of the mirror supporting It maythus be seen that we have invented noveland highly useful improvements in Locke level structure, permitting the device to be simply manufactured and easily used. The device, unlike similar surveying instruments, may be maintained in a substantially dust-tight condition. Its adjustments may be made to fine degrees, and with a precision normally found only in far more expensive surveying instruments. The device includes a leveling element which may be removed from the main tube element, although critical adjustments may be made without so doing, should the same become necessary after installation. The device is sturdy and durable, and will withstand much rough handling without adverse effects.

We wish it to be understood that we do not consider the invention limited to the exact details of structure shown and set forth in this specification, for obvious modifications will occur to which the present invention pertains.

We claim:

l. A leveling element for use in a surveying instru ment, including a fixed member disposable within the main optical tube of said surveying instrument and fixedly supporting a bubble tube; a mirror positioning member axially and slidably member, and-to said bubble tube; and positioning of said mirror with respect to said fixed memher in operative alignment with said bubble tube, said means including a locking screw engagable with a slot in said mirror positioning member ing in said fixed member; said screw including a head portion and threaded shaft portion, said portion having a slot for engagement with a screw driver, said threaded shaft portion having a second engagement slot engageable with a second screw driver.

2. A leveling element for use in a surveying instrument, including a fixed member disposable within the main optical tube of said surveying instrument and fixedly supporting a bubble tube; a mirror positioning member axially and slidably disposed with respect to said fixed member, and to said bubble tube; and means to fix the positioning of said mirror with respect to said fixed member in operative alignment with said bubble tube, said means including a locking screw engagable with a slot in said mirror positioning member and a threaded opening in said fixed member; said screw including ahead por' tion and a threaded shaft portion, said portion having first means for engagement with a tool, said threaded shaft portion having second means enegageable with a second tool.

References Cited in the file of this patent UNITED STATES PATENTS those skilled in the art to disposed with respect to said fixed means to fix the and a threaded open 

